Subscribers to wireless communication systems employing the well-known ANS-41 signaling protocol standard may, at times, roam outside their home system and into wireless communication systems employing the well known GSM standard. Assuming that the subscribers have user equipment or mobile-stations operable to function in either wireless communication system, some form of authentication needs to be performed before the GSM based wireless communications system can provide any type of service to the subscribers of the ANS-41 based wireless communication systems. However, the manner in which authentication is performed in GSM and ANS-41 based wireless communication systems are different. Accordingly, there exists a need for providing authentication for a subscriber to a ANS-41 based wireless communication system roaming into a GSM based wireless communication system, and vice-versa.